var flag = true;
function show_menu() {
    var menu1 = document.getElementById("menu1");
    if (flag) {
        menu1.style.display = "block";
        flag = false;
    } else {
        menu1.style.display = "none";
        flag = true;
    }

}
function show_menu1(){
    var menu1 = document.getElementById("menu1");
    menu1.style.display = "none";
    flag = true;
}